Google App Engine users may have some migration work ahead of them, because Google is contemplating not upgrading some popular programming languages currently running on the service, notably Java and Python.

Instead, the company may support the language upgrades only in the second iteration of Google App Engine, which the company has been calling, internally, Google App Engine 2.

“We’ve been in decision mode on how much language support do we bring to existing App Engine models,” said Brian Stevens, Google vice president of cloud platforms, during an interview with IDG News Service.

In other words, Google might upgrade App Engine to support the latest versions of Java and Python, Java 8, and Python 3. But it also might not.

If Google doesn’t upgrade, current users of the Java and Python services will have to replant their applications on the new services instead, should they want the language updates.

A Google spokesperson confirmed that the company is in “decision mode” about supporting these languages in the current, though possibly soon-too-be legacy, version of Google App Engine.

Installing a new version of the language on the cloud service requires “a lot of surgery,” Stevens admitted.

Instead, the company is planning to offer these languages as managed virtual machine services on the Google Compute Engine.

This approach packages the run-time within a virtual machine, which makes it easier for Google to support multiple versions of a language. For the user, it provides a greater range of configuration possibilities when it comes to choosing accompanying storage and CPU services.

This managed virtual machine approach may one day replace the current model of Google App Engine outright, Stevens said.

Currently, Google App Engine offers Java 7, which Oracle ceased further development on in April in favor of advancing Java 8. Google uses the OpenJDK to run its Java services, which is maintained as an open source project outside of Oracle, and which will still support Java 7 indefinitely.

“The question here is how heavily Google App Engine is used for Java and whether it is worthwhile for Google to do the Java support,” IDC analyst Al Hilwa said via email. He noted that running a platform service for an individual programming language such as Java or Python “requires a lot of engineering specific to the language run-time.”

The topic has been of ongoing concern to at least a few customers, who voiced their questions on Google group forums.

“I am wondering if anyone can comment on whether it is even planned to implement Java 8 support on good old App Engine,” wrote one user, noting that the update had been requested two years ago, and Google hasn’t yet responded to the ticket.

Python support is in a similar state of limbo. Google App Engine currently offers Python version 2.7, but there is no word on supporting any of the 3.x versions in Google App Engine.